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4G/3G/WiFi

VoLTE to Drive IMS Renaissance?

It is clear now – if there ever was any real doubt – that IP Multimedia Subsystem (IMS) is the preferred choice of mobile operators to support voice service in LTE networks, and specifically that the IMS-lite "VoLTE" mechanism will be the first step toward actually implementing it.

Yes, there is irony in the fact that plain old voice telephony is the application that looks set to pull through IMS into broad usage within mobile networks. And yes, circuit-switch fallback and dual-radio devices will serve as useful interim mechanisms for some operators. But in the context of a ten-year LTE planning horizon, the transition to IMS-based call control is desirable, achievable and more efficient than stopgap alternatives.

What's interesting, and also more debatable, is the extent to which VoLTE could set the stage for a more fundamental transition to operator-provided real-time, rich-media services. This is one of the themes discussed in my recent Heavy Reading report, "Voice Over LTE, IMS & the Future of Rich-Media Services in the 4G Era."

A strength of the GSM Association (GSMA) -backed "VoLTE Initiative" is that it provides a simple set of features intended to be reasonably straightforward to implement. The industry now has guidance on use cases, service features, roaming interfaces, and so on, such that it should be possible to at least match the service capability of the existing circuit-switched domain used in 2G and 3G networks.

That is nice to have, but not compelling. A core tenet of the initiative, therefore, is for VoLTE to serve as the starting point for a more complete 3rd Generation Partnership Project (3GPP) IMS implementation capable of supporting a richer service set, as and when operators want to pursue this evolution path. Forward and backward capability between VoLTE and full IMS is what makes this possible. A VoLTE device, as shown below, can operate on a network running full 3GPP IMS, and a 3GPP IMS-compatible device can run on a network that supports VoLTE only.



This is, theoretically, very powerful. Operators can introduce VoLTE without having to fully implement IMS, and then evolve the network over time as end-user requirements and demand for rich media become clearer and as technology matures. Similarly, handset makers can create devices that support 3GPP Release 8 and Release 9 functions that work with a VoLTE network and are also prepared for network and service evolution.

If you believe that IMS is the answer for "call control" in all IP mobile networks (there's no real alternative), then VoLTE is the logical starting point. Even if you have doubts about IMS over the long term, VoLTE provides a practical solution that – although challenging to implement in some aspects (e.g., handover between LTE and 2G/3G) – should be a deployable solution for most reasonably advanced operators.

Can operators reinvent and extend the voice model into billable rich media services? I think it's too early to say, but at least with this approach, the potential is there and investment won't be sunk into interim measures that close off that route to innovation.

— Gabriel Brown, Senior Analyst, Heavy Reading


For more information about Heavy Reading's "Voice Over LTE, IMS & the Future of Rich-Media Services in the 4G Era," or to request a free executive summary of this report, please contact:




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JeddChen 12/5/2012 | 5:14:16 PM
re: VoLTE to Drive IMS Renaissance?

Very good points to give reader a clear thinking on the evolution path of VoLTE to full IMS. Be grateful if you can share the detailed report with me.


Actually if only for voice over LTE the mobile softswitch is still a possible choice for Core network for its maturity when IMS is not strong enough for large-scale network.

JeddChen 12/5/2012 | 5:14:14 PM
re: VoLTE to Drive IMS Renaissance?

Thank you very much ,Gabriel, for your informative update with a brief word.


Gabriel Brown 12/5/2012 | 5:14:14 PM
re: VoLTE to Drive IMS Renaissance?

Thanks JeddChen. Yes, SIP-enabled MSCs could be used for voice over LTE and would be VoLTE-compliant. One advantage is that back-end integration is theoretically much simpler, since billing, etc, is already in place.


This is what NSN is doing with its "Fast Track" appraoch, although it also has a full IMS offer as well, which it sees as the long-term answer.


From what I hear from various carriers, this would be used in smaller or mid-sized markets. I haven't yet heard from a very large operator that they intend to take this route, although that may be more a reflection on my information than anything else.


Ericsson is not suporting this approach because it doesn't evolve to richer applications. It is focused on full IMS.


Huawei seems to favor full IMS, but would probably do this if there was a reasonable sized deal on the table.


VOIP afficinadios don't tend to like the MSC upgrade appraoch on principle. They argue that reusing old code will come back to bite you later.


Then there's the CS Fallback option...


 

paolo.franzoi 12/5/2012 | 5:14:13 PM
re: VoLTE to Drive IMS Renaissance?

 


Man I am sure that IMS can drive some really cool applications that are not already available for free over the web like video calling and voip and IM and oh wait...


I mean seriously.  Once people sit back they will realize there are no great future applications that are not done over the web that are done via IMS and that carriers will simply waste a boat load of money investing in this stuff.


seven


 

Gabriel Brown 12/5/2012 | 5:14:12 PM
re: VoLTE to Drive IMS Renaissance?

Hi seven -- The rich-media part is speculative, obviously.


Meanwhile, do operators want to offer a toll-grade voice service in LTE that provides equivalent service to today's CS domain?


If you think not, then fine.


If yes, then what are the options?


Two other points:

<ul>
<li>Using VoLTE does not preclude so-called over-the-top services, which will be popular. Again that's obvious.</li>
</ul>
<ul>
<li>It seems likely that for the next two or three years 3GPP operators will elect to keep smartphones on HSPA+ since these devices don't really need LTE.</li>
</ul>
paolo.franzoi 12/5/2012 | 5:14:11 PM
re: VoLTE to Drive IMS Renaissance?

Dan,


&nbsp;


See Skype...you ALREADY have all those options. &nbsp;That is the point. &nbsp;All that happens is that these options get copied from existing services. &nbsp;Large operators don't innovate them so copying them at the point that they are commodities makes no cents (humor). &nbsp;This is especially true when the voice services already exist and so the expenditure to support them has already been made.


So, what you get to do is expend a whole lot of capex to offer services you and the other services already do. &nbsp;Carriers will say "value-added". &nbsp;The theory exists ONLY if the service does not already.


seven


&nbsp;

paolo.franzoi 12/5/2012 | 5:14:11 PM
re: VoLTE to Drive IMS Renaissance?

&nbsp;


Gabriel,


Since there is no money in voice, then unless you are saving money run it as it runs today. &nbsp;Once there are money savings then run with standard VoIP switches.


&nbsp;


seven


&nbsp;

Dan Warren 12/5/2012 | 5:14:11 PM
re: VoLTE to Drive IMS Renaissance?

Interesting discussion all ways around.&nbsp; I have a&nbsp;couple of&nbsp;comments.


1) The implementation options for an IMS-based VoLTE solution are many, and whilst they will vary from operator to operator, vendor to vendor, the key point that I have tried to push through out the work that GSMA has been doing on this is that the three interfaces that demand interoperability are fundamental - the UNI, the NNI for interconnect and the 'Roaming NNI'.&nbsp; What makes CS voice work is that everyone implements these things pretty much the same way, so for a VoLTE ecosystem to develop, the same technical principles need to apply.&nbsp; What you do in your own network is (literally) your business - so leverage MSC's if you want, build from scratch if you want -&nbsp;but where you expose an interface to other operators, you need to play by the rules for the good of everyone.


2) The comment on the support of 'new' services like video, IM and the rest.&nbsp; Yes, this does all seema bit old hat, but I refer you back to the first point as the added value.&nbsp; Suppose instead of only being able to IM or video call those people on the same provider as you (be that ASP, operator or whatever), you could use those services to anyone.&nbsp; Suppose instead of just having the choice of 'Call, SMS, MMS this contact' you also had IM, video call and who-knows-what-else?&nbsp; If this could be done without the need to think that you need one app for one set of contacts, a different app for another set or a different service, in fact this could be done from a contact list, is that a better service experience?&nbsp; This has always been what IMS was intended for - the reason it hasn't happened is because the revenue from such services is pretty tough to identify in the face of Internet price points, and made the investment in IMS a tough ask for just that set of services.&nbsp; If however, a voice service with all the revenue stream that comes with it drives the IMS CapEx outlay, then adding on the bells-and-whistles is a relatively small outlay for a whole bunch of incremental user experience.


Obviously I am bias in this discussion, but I did want to put the case for what we're doing in GSMA land, and why we're doing it.&nbsp; Gabriel's point about 'what's the alternative' is equally valid.&nbsp; Essentially, someone had to do something.&nbsp; It just happens to be us doing it.


&nbsp;

Gabriel Brown 12/5/2012 | 5:14:10 PM
re: VoLTE to Drive IMS Renaissance?

That is the crux of the issue. Voice is a commodity, and in some cases declining in overall revenue terms. So the investment case is harder. Who wants to invest in a declining revenue stream?


But in a new LTE network, do you want to support voice service to the standard people are used to? Probably yes, so then how?


LTE does not support CS domain, so you can't continue with that unless you force your user off the shiny new network to existing 2G/3G. This is kludgy, but yes, the CS Fallback option is being implemented as well.


To your point on&nbsp;"VOIP switches", that's not really an issue. MSC Servers are not all that expensive in the scheme of things.


The primary challenge with VoLTE is SR-VCC (handover from LTE to 2G/3G during the call).

paolo.franzoi 12/5/2012 | 5:14:07 PM
re: VoLTE to Drive IMS Renaissance?

&nbsp;


Gabriel,


I guess my question is "what is wrong with today's voice service using today's technology"?&nbsp; There are 3 costs here:


1 - The cost of maintaining the existing infrastructure


2 - The cost of handsets that support both standards


3 - The costs to buy and integrate a new switching technology.


My baseline theory (and carrier hate it) is that their idea of value added service is dead and the sooner they stop trying to make them the better off they will be.&nbsp; My issue with IMS is not with the technology itself, it is that carriers would make a decision based on buying something to create these services (which I consider an utter waste of time).&nbsp; As to measuring what is the cheapest way to offer voice over a handset that will serve data over LTE, I am opinionless.&nbsp; But whatever the cheapest way is, that is what should be done.


The bad news is that carriers will chase this fantasy of upping the price of bits and vendors will support this dream.&nbsp; Then reality will set in and they find that they are spending a lot of money.&nbsp; It is not just that the price for voice bits is going down but the price for all bits is going down.&nbsp; The last service that carriers have tried adding is video.&nbsp; I am wondering if anyone has done an ROI for FiOS or for U-verse.&nbsp; Interesting to see if in particular if AT&amp;T made more money off of U-verse or its old partnership with DISH.


seven


&nbsp;

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